Share Repurchase Program - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) shares	Nov. 04, 2017 USD ($)
Equity [Abstract]
Stock repurchase program, authorized amount	$ 75,000,000	$ 100,000,000
Line of credit facility, conditions for the elimination of limits on shares repurchases, leverage ratio	3.25
Stock Repurchased During Period, Shares | shares	684,335
Stock Repurchased During Period, Value	$ 30,700,000
Stock repurchase program, remaining authorized repurchase amount	$ 100,000,000